For one brief moment, it appeared that the Democratic presidential primary would finally have fewer candidates than the 2016 Republican field at its peak. No longer. With the potential entry of former New York City Mayor Michael Bloomberg and the actual entry of former Massachusetts Gov. Deval Patrick into the race, we are essentially back to 16 “serious” candidates (18 if you are willing to count former Rep. Joe Sestak and Miramar, Fla., Mayor Wayne Messam).

What is going on?  I think we have to look at three issues separately: Mayor Bloomberg, Governor Patrick, and the possibility of a brokered convention. When all is said and done, this is mostly about Joe Biden’s troubles in the race, as well as elite heartburn about the potential for Sen. Elizabeth Warren or Sen. Bernie Sanders winning the Democratic nomination.

1. Michael Bloomberg. I think Bloomberg’s possible entry offers little real insight into elite perceptions about the state of the Democratic race. Bloomberg is possessed of a massive ego, and his links to the Democratic establishment are tenuous, to say the least (he was elected mayor of New York first as a Republican and later as an independent).

To the extent his candidacy would be at all remarkable, it is because it makes some degree of sense.  I don’t think Bloomberg is going to be the nominee, but I think he’s more likely than  Julian Castro or even Cory Booker to become the standard-bearer. Bloomberg has a nearly bottomless well of money from which to fund his campaign. He is probably the one candidate who could skip the early four primaries, as he intends to do, and nevertheless scoop up delegates on Super Tuesday.  In other words, Bloomberg is doing this because he perceives Joe Biden as weak, and sees the possibility of a brokered convention. That is important, but not as important as the implications of Patrick’s entry.

2. Deval Patrick. His entry is much more consequential, even though he probably has less chance of becoming the eventual nominee than Bloomberg. It must be viewed in a couple of contexts. First, it comes on the heels of a (poorly received) Eric Holder trial balloon.  Second, Patrick, like Holder, is an Obama ally. 

The best way, then, to interpret the Holder feint and Patrick’s entry is as a shot across Biden’s bow, and as an expression of deep concern among Democratic Party actors about the electability of Warren and Sanders.  Biden’s campaign has been plagued by problems from the outset. The best remaining arguments for him becoming the nominee have been that he is Obama’s supposed heir, and that he maintains a sizeable African American firewall in South Carolina and throughout the South. 

Patrick’s entry is a frontal assault upon both of these arguments. His candidacy likely would not happen without substantial support from other people in Obama’s orbit (including, possibly, the former president himself).  Translated, this suggests that Biden cannot count on endorsements, tacit or otherwise, from important players in the previous administration.  Second, it suggests that his support among African Americans should not be considered secure. While I would be surprised if Patrick received an endorsement from Obama, I suspect he will receive some endorsements from Obama proxies. 

The interpretation here would be that Biden is effectively the Jeb Bush of the 2020 Democratic field: His main function has been to prevent time, money, energy and attention from flowing to other moderate candidates, and thereby enabling the rise of Warren and Sanders. By removing the two best arguments for Biden’s continued candidacy, the theory goes, his 25% of the vote should start to look around. If he were to collapse or even drop out, it would open up space for Pete Buttigieg, Amy Klobuchar, or any of the other moderates to rise.

3. Brokered Convention. The final possibility here is that Bloomberg sensed the rising possibility of a brokered convention and that Patrick is trying to make it happen. Bloomberg all but guarantees there will be three serious candidates fighting on Super Tuesday, and possibly four or five.  Patrick increases the chances of three or four different candidates winning the early four contests.

For the Democratic establishment, that would be fine.  It would almost certainly deny Sanders the nomination, and might even open the possibility of a “savior” candidate (Hillary? Michelle?).  Though a brokered convention is still an outside possibility, its odds are growing right now.